Display structure and display device

Abstract

A display structure (1000), comprising a waveguide (1100) comprising a first face (1110), a second face (1120) opposite the first face (1110), and an in-coupling region (1112) on the first face (1110); an in-coupling structure (1200) for coupling an optical beam (1201) into the waveguide (1100) via the in-coupling region (1112); and an out-coupling structure (1300) configured to perform exit pupil expansion by pupil replication and to couple light from the optical beam (1201) out of the waveguide (1100). The in-coupling region (1112) has a maximum width, Wmax; the waveguide (1100) has a thickness, T, greater than 0.25×Wmax; and the out-coupling structure (1300) comprises a diffractive first out-coupling element (1310) and a diffractive second outcoupling element (1320) at least partly laterally overlapping the first out-coupling element (1310).

1 . A display structure, comprising:
 a waveguide comprising a first face extending laterally along a base plane, a second face opposite the first face, and an in-coupling region on the first face;   an in-coupling structure for coupling an optical beam into the waveguide via the in-coupling region for propagation in the waveguide by total internal reflection; and   an out-coupling structure configured to perform exit pupil expansion by pupil replication along at least a first replication direction and to couple light from the optical beam out of the waveguide;   wherein the in-coupling region has a maximum width, W max , measured along the first replication direction; the waveguide has a thickness, T, measured from the first face to the second face, greater than 0.25 times the maximum width, W max , of the in-coupling region; and the outcoupling structure comprises a diffractive first out-coupling element and a diffractive second out-coupling element at least partly laterally overlapping the first out-coupling element.   
     
     
         2 . The display structure of  claim 1 , wherein the thickness, T, of the waveguide is greater than or equal to 0.3, or 0.35, or 0.4 times the maximum width, W max , of the in-coupling region. 
     
     
         3 . The display structure of  claim 1 , wherein the in-coupling structure comprises a diffractive in-coupling element. 
     
     
         4 . The display structure of  claim 1 , wherein the in-coupling structure comprises an in-coupling prism. 
     
     
         5 . The display structure of  claim 1 , wherein the first out-coupling element is arranged on the first face, and the second out-coupling element is arranged on the second face. 
     
     
         6 . The display structure of  claim 5 , wherein the out-coupling structure further comprises a diffractive third out-coupling element arranged within the waveguide, the third out-coupling element at least partly laterally overlapping each of the first out-coupling element and the second out-coupling element. 
     
     
         7 . The display structure of  claim 6 , wherein the thickness, T, of the waveguide is greater than or equal to 0.5, or to 0.6, or to 0.7, or to 0.8, or to 0.9 times the maximum width, W max , of the in-coupling region. 
     
     
         8 . The display structure of  claim 1 , wherein the thickness, T, of the waveguide is less than or equal to 0.5 times the maximum width, W max , of the in-coupling region. 
     
     
         9 . The display structure of  claim 1 , comprising a display engine for directing the optical beam to the in-coupling structure. 
     
     
         10 . A The display structure of  claim 9 , wherein the display engine is implemented as a scanner-based display engine, e.g., a laser-scanning display engine. 
     
     
         11 . A display device, comprising a display structure according to the display structure of  claim 1 . 
     
     
         12 . The display structure of  claim 11  implemented as a see-through display device. 
     
     
         13 . The display structure of  claim 11  implemented as a head-mounted display device.